Theory about Cassidy and the line of "I will put you back together".

Everyone pretty much knows that Cassidy is the name of the GF child speaking in the logbook. So this means that BV isn't Golden Freddy. But this girl has apparently seen BV, and confused Michael with BV, as evident by the line "the party was for you. This means that this girl knows about BV and his struggles. And has met BV at some point in FNaF 4, and that strikes me as the key to knowing who the ever so mysterious speaker in the night 6 cutscene of FNaF 4 is who promises to put BV "back together".